Multidisciplinary LEMS treatment found to ease symptoms for man, 40

Comprehensive care needed in case of patient with B-cell lymphoma: Report

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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An illustration for a rare disease, showing one red figure in a mass of people.

A 40-year-old man who developed Lambert-Eaton myasthenic syndrome (LEMS) secondary to a cancer of the lymphatic system saw his LEMS symptoms ease only after he received comprehensive treatment involving several medical specialties, according to a case report.

The patient, who had a type of B-cell lymphoma, developed weakness in his legs — a classic sign of LEMS — that was successfully treated with the aid of the hospital’s hematology, neurology, and rehabilitation specialists.

“We believe that patients with LEMS require multidisciplinary treatments in which multiple departments cooperate to improve symptoms,” the researchers wrote.

His case was described in a study titled “Lambert-Eaton myasthenic syndrome with primary thymic marginal zone B-cell lymphoma: A case report,” published in the journal Respirology Case Reports.

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A rare autoimmune disorder, LEMS affects the neuromuscular junction, which is the region where nerves and muscles meet and communicate. In LEMS, the immune system mistakenly attacks voltage-gated calcium channels (VGCCs) in nerve cells that control muscle contraction, leading to muscle weakness and fatigue, particularly in the arms and legs.

In about half of all cases, LEMS is associated with an underlying cancer, most commonly small cell lung cancer (SCLC), an aggressive form of lung cancer.

In this report, a team of researchers in Japan described the case of a patient in whom LEMS developed in association with a type of B-cell lymphoma.

The patient sought hospital treatment after experiencing weakness in both legs for six months. His medical history included Perthes disease — a childhood condition that affects the hip joint — at age 12, as well as systemic lupus erythematosus and Sjögren’s syndrome, two chronic autoimmune disorders.

He was a heavy smoker, smoking 20 cigarettes a day, but didn’t take any medication. A clinical examination showed a Gower’s sign, a type of maneuver used by patients with muscle weakness in which they use their hands to help lift their body when rising from the floor. He also showed weakness in both legs and was unsteady when standing on one leg.

A nerve conduction test, which measures how well and how fast an electrical impulse moves through a nerve, showed improvements in muscle strength following exercise, consistent with LEMS.

Blood work also revealed the man had high levels of antibodies against P/Q-type VGCCs, leading neurologists to diagnose him with LEMS.

A contrast-enhanced CT scan revealed a mass in the mediastinum, an area in the chest that holds the heart and several other important structures.

The mass had multiple cysts inside, indicative of a potential thymoma, or a tumor in the thymus gland, or possible thymus enlargement, or lymphoma.

The patient then underwent fluorodeoxyglucose-positron emission tomography (FDG-PET), an imaging technique that uses a small amount of a radioactive tracer, called FDG, to identify sites of abnormal glucose or blood sugar metabolism, common with tumor cells.

The mediastinum mass came out positive, as did lymph nodes in the armpits.

He was referred to the thoracic surgery department and the mass — measuring around 13 centimeters — was removed by robot-assisted surgery.

Additional analyses of the removed mass confirmed the diagnosis of a B-cell lymphoma.

The patient was discharged 11 days after undergoing surgery. One month later, he was referred to the hematology department to receive treatment with rituximab (sold as Rituxan, among other brand names), an approved treatment for lymphoma. However, his LEMS symptoms did not ease.

Two months after surgery, he was transferred to the neurology department where he received a three-day steroid pulse therapy with methylprednisolone, along with diaminopyridine, and a five-day into-the-vein (intravenous) infusion of immune globulins. He also was given azathioprine, an immunosuppressive agent, and started rehabilitation.

His LEMS symptoms gradually eased following the treatment combination.

We have succeeded in treating LEMS symptoms by providing comprehensive patient care with the cooperation of the haematology, neurology, and rehabilitation departments.

On his annual CT scan, no signs of masses in the thymus or lungs were detected. At the time of the report’s publication, the patient was being treated with 60mg of diaminopyridine and 100mg of azathioprine.

“We have succeeded in treating LEMS symptoms by providing comprehensive patient care with the cooperation of the haematology, neurology, and rehabilitation departments,” the researchers wrote, noting “malignancy treatments alone do not improve the neurological symptoms in LEMS patients.”